Solid state drives use silicon chips instead of the storage platters employed by traditional hard drives. The thin black rectangles on the solid state drive circuitboard to the left side of the picture are the SSD's memory chips.

A high-capacity solid state drive can be built into a thin, compact package for notebooks and other mobile devices, but SSDs can also be built to the same dimensions as standard slim hard drives to make it easier for manufacturers to build them into existing electronic gadgets. Seen here, Toshiba SSDs are pictured on the right-hand side of the pyramid, and standard mobile hard drives are on the left. (Chad Sapieha)

If you've been browsing for a new laptop in recent months, chances are you've heard about a hard disk replacement technology called a solid-state drive (SSD). Apple, for example, offers consumers the ability to swap out the traditional hard disk in its new MacBook Air for a 64-gigabyte solid-state drive, and similar options exist for many tablets, ultra-portables, and notebooks available from most major manufacturers.

Should you decide to exercise your option for a solid-state drive you'll probably be adding between $800 and $1,000 to the price of the machine. The question, obviously, is why would anyone choose to spend so much money on something as mundane as storage?

To answer that, we need to learn more about what a solid-state drive is.

SSDs are based on solid-state memory, a microchip technology that has been around for decades. It exists in several forms, ranging from ubiquitous RAM — short for Random Access Memory (RAM), the memory found in almost all computers — to the flash-memory cards used to store content in mobile phones and digital cameras, to the embedded storage media used in some portable music players and camcorders.

The particular kind of solid-state technology typically used for solid-state drives in PCs and notebooks is called NAND storage. It has a significant advantage over other types of solid-state storage: NAND is non-volatile, which means it can reliably retain information over long periods regardless of whether it's connected to a power source.

Benefits of SSDs

All solid-state drives share one important distinction from hard disk drives: they have no moving parts.

A traditional hard disk drive has platters that spin thousands of times per minute, and information is magnetically encoded on these platters by a tiny device called read/write head (think of it a bit like a tone-arm on an old vinyl record player — it travels across the surface of the platter reading the tracks of stored information). A solid-state drive, in contrast, is basically a computer chip, or a series of linked chips. Each chip has billions of stationary crystalline cells, each of which can be turned on or off via an electrical charge to represent the zeroes and ones of binary information — the "language" computers speak to run programs and store information.

This lack of moving parts is what gives solid-state drives their biggest advantage over hard disk technology: less wear and tear and no possibility of mechanical failure, which results in enhanced durability and security of data.

Jerome Kudera, an engineer and notebook product manager with Toshiba, a manufacturer of both hard disk and solid-state drives, explained that a mechanical drive can withstand an impact of only 0.5 g's before suffering damage caused by a read/write head crashing on its platter. By contrast, a solid-state drive can easily absorb shocks of up to 20 g's. Plus, solid-state drives can withstand and operate in extreme temperatures ranging from -25 to 85 degrees Celsius. As a result, it's almost impossible to damage a solid-state drive under normal use.

Speed boost

Without moving parts, solid-state drives can also access data more efficiently than a hard disk, leading to a noticeable boost in performance.

At the Consumer Electronics Show held in Las Vegas in January, Toshiba demonstrated how a computer equipped with a solid-state drive halved the amount of time required to load and boot up Windows Vista in a notebook, from one minute to 30 seconds.

PC manufacturer Hewlett-Packard has conducted tests of its own that confirm solid-state's performance advantage. Its experiments showed that an off-the-shelf HP notebook outfitted with a solid-state drive was able to access information more than 60 times faster than it did with a hard disk drive. The machine was also able to transfer more than twice as much data per second.

A performance increase of this kind won't have a perceptible impact on everyday computing tasks that happen almost instantaneously already, such as accessing a word processing document or opening an internet browser. However, it will be noticeable to users running applications that need to quickly access and transfer large amounts of information, such as video editing programs and high-end PC games.

It's also something that can offer hard-core gamers more performance from their existing computers. Rahul Sood, founder of Calgary-based luxury computer manufacturer VoodooPC, said he expects gamers to be key early adopters of solid-state drive technology. "They (SSDs) have already entered the gaming space,” he noted.

Power consumption

Solid-state drives reduce energy usage, too.

With no machinery to move, SSDs have an active power consumption of just a single watt, as opposed to the nearly four watts sucked up by traditional hard disks. That means they run cooler, and, more importantly, have the potential to prolong a notebook's battery life — a key selling feature for many portable PC consumers. Some manufacturers estimate that current laptops could operate up to 30 minutes longer per charge if their hard disks were replaced with solid-state drives.

Figures from market research firm Gartner Research forecast that by 2010 roughly 20 per cent of notebooks sold worldwide will ship with solid-state drives.

The rest of the benefits offered by solid-state drive technology are likely to appeal to consumers' aesthetic sensibilities. Depending on the storage capacity required, SSDs are capable of being manufactured in very thin packages that can potentially help decrease the bulk of some computer products, such as ultra-portable PCs.

They may also help users take a load off — a 1.8-inch 128-gigabyte drive weighs less than 100 grams, whereas a hard disk of similar size and capacity tips the scales at around half a kilogram.

And with no moving parts, there's nothing to make sound, resulting in zero acoustic noise or vibration.

The caveat

The list of reasons solid-state storage might be desirable is clearly long and varied. But it does have a couple of notable disadvantages: relatively small capacity compared to hard disk drives, and a prohibitive price.

The highest capacity SSD currently available to consumers that has dimensions compatible with existing hard disk drive bays is 128-gigabytes, but these drives cost several thousand dollars and aren't yet offered as an option by most PC makers. At the moment, 64-gigabyte models that cost around $1,000 represent the best combination of affordability and capacity.

Samsung ultraportable retrofitted with SSD at CES.jpg: A solid state drive is shown on the circuitboard of a portable media player that was originally designed to take a slim hard disk drive. (Chad Sapieha)

According to solid-state drive manufacturer Samsung Semiconductor, 64-gigabytes will generally meet the needs of most business users — people who typically don't load their work machines with lots of multimedia files.

Of course, there's still the issue of price, but Jim Elliott, a spokesperson for Samsung, believes that some businesses are ready to pay a premium for durability and reliability. He says SSDs offer a value proposition similar to hybrid cars. "You pay a bit more up front for a hybrid, but you recoup that cost over time by paying less for gas and driving in the car pool lane to save time," he explained. "Now, if you need to buy a thousand laptops for your company and factor in a five per cent failure rate for standard hard disk drives and lost productivity due to down time, solid-state might drop the failure rate enough to warrant the increased cost."

Elliott added that some non-business consumers will be willing to make the switch right away. "Anyone who's ever lost family pictures in a hard disk failure," might be willing to pay extra for solid-state's enhanced reliability.

Plus, prices continue to drop even as solid-state density — which directly affects storage capacity — grows.

"The density in the NAND space has been doubling every year for the last eight to 10 years. We'll be at a terabyte in a short time," said Elliott.

Indeed, many PC companies are banking on solid-state drives slowly but surely replacing hard disks. HP's Darren Leroux said his company already offers half a dozen notebooks and a tablet with a solid-state drive option, and pointed to forecasts produced by Gartner Research that suggest by 2010 roughly 20 per cent of notebooks sold worldwide will ship with solid-state drives.

While solid-state drives may be destined to become commonplace in years to come, picking one up in 2008 will almost certainly leave a sizeable dent in your bank account. If you happen to be ordering a new notebook and can't afford to tick off the checkbox to upgrade to a solid-state drive, take comfort in the knowledge that while you may be restricted to a hard disk drive for now, there's a good chance that a solid-state drive will come standard in your next portable PC.